Viscosity studies of some narcotic-analgesic drugs in aqueous-alcoholic mixtures at 25 °C

Viscosities of drugs namely Parvon Spas, Parvon Forte, Tramacip and Parvodex in various aqueous mixtures of alcohols (methanol, ethanol and I -propanol) have been determined. These studies are further extended for solutes like the electrolyte sodium chloride, the surfactant: sodium dodecyl sulphate and the non-electrolyte sucrose in the presence of these drugs. The viscosity data have been analyzed for the evaluation of A and B viscosity coefficients using Jones-Dole equation. A-coefficients are found to be negligible implying weak ion-ion interactions whereas B-coefficients are found to be positive thereby showing drug-solvent interactions. It can be inferred from these studies that all the drug cations can be regarded as structure-makers/promoters due to hydrophobic hydration of the drug molecules. Furthermore, the results are correlated to understand the solution behavior of drugs in aqueous alcoholic systems as a function of the nature of alcohols and different types of solutes. (C) 2007 Elsevier B.V. All rights reserved.